Yes they very much can and its possible if the cell is left in presence of another mutagen that brings about an opposite effect or it can be made possible by the repair mechanisms.are there any other ways?? there should be... does anyone over here know of any more?

Do I take it that the reason it's hard to 'reverse' a mutation is that since mutations are by definition random, the number of 'wrong' versions of the nucleotide sequence are far greater than the number of 'right' versions, so there is statistically more likelihood of a mutation from a correct sequence than a reversion to a correct sequence from a mutation.

its basically like if there is 1/10 th a chance for a mutation then the chance for reverse mutation is also 1/10th. So basically if we were to observe the reverse mutation in the environment its possibility is 1/100th. thats what i believe for there must be a mutation before there can be a reverse mutation.

jwalin wrote: thats what I believe for there must be a mutation before there can be a reverse mutation.

You like tautologies, don't you? of course there will be no reverse mutation in absence of a preexisting mutation. Duh.

What I am trying to explain, is that the exact reversal of a mutation is quite unlikely (though not impossible) because the probability of a given mutation to happen is quite low, and then you expect it to un-happen your are squaring the unlikelihood And we are talking about point mutations here. If a deletion happens or an insertion, or a change in chromosomal structure, the probability that it un-happens is even lower.On the other hand what is seen is that compensatory mutations are selected for. Changes that either correct or give a fitness advantage sufficient to make up for the cost of the mutations. It can be measured and observed easily in bacteria. If a first mutation provides resistance to an antibiotic at a fitness cost (often the case), of course it will still be maintained as long as the antibiotic is here, as the other option is death. But when the selective pressure is lifted, instead of reversal to the original sensitive phenotype, what is often observed is the accumulation of compensatory mutations that restore fitness to close to the original, while maintaining the resistance.

Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)

BTW about the post that i had made hmm i am sorry lol. because just before that i was helping a guy with a few of his queries and i had to make sure that i dont leave out any detail for that would be the end of the world. Hangover sort of effect. My bad lol.

hello , i am happy to joine with you. i want to say about Mutated cells .mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. Due to the damaging effects that mutations can have on genes, organisms have evolved mechanisms such as DNA repair to remove mutations. Mutations can involve large sections of DNA becoming duplicated, usually through genetic recombination.

There are probably millions of mutations that happen each day in the human organism, but as JB pointed out, the DNA repair system fixes them. The other alternative is that the cell can go down the apoptosis pathway (as in a self-destruction option). Now if the mutation can bypass the DNA repair system and the apoptosis pathway, then it has become its own identity/specific cell. By the time this specific cell has replicated itself, and has become known to the organism, the theory for reverse mutations is mute/pointless to the affected organism.